Currently, television receivers in North American homes are able to obtain Electronic Program Guide (EPG) data through the Vertical Blanking Interval (VBI) of NTSC signals. These are carried on a specific terrestrial channel (typically a local Public Broadcast Service (PBS) station) or on a specific cable TV station. Starsight Telecast.TM. is one provider of a VBI EPG service and typically charges a fee of $6 per month.
The television receiver includes special hardware and software designed or licensed by Starsight to the various television manufacturers. The format of the transmission is proprietary as is the hardware and software used in the television receiver to decode and display the information. The data rate of the data transmission is 960 bps. The EPG data signal contains information for every cable system and terrestrial TV station in the area covered by the PBS station resulting in a great portion of the received data being of no use to the viewer. This system has a drawback in that, given the slow communications speed and the amount of data sent, it may take as long as 12-24 hours for a particular user to obtain a complete data set.
Acquisition of the EPG data is accomplished only if the television receiver is tuned to the specific channel that carries the transmission. Typically, this requires the television receiver be tuned to the provider channel (i.e. PBS) while the television is not in use, such as overnight.
Another system for providing EPG data through the VBI is planned by Gemstar. However, these broadcasts will be provided by the networks such as ABC, NBC, CBS and their affiliates. This system has the drawback that the networks will only provide their own respective programming information. Therefore, the viewer will be required to select each and every channel over a period of time in order to build up a collection of schedules for all of the television stations of interest.
Other service providers, such as DirecTV.TM., Primestar.TM. and Echostar.TM., also provide EPGs through special transport packets in the digital data stream of the signal. This same approach will be used by Digital Cable and Wireless Cable services (MMDS).
With the increased popularity of PCs and the advent of the Internet, certain companies now provide EPGs over the Internet. These EPGs are accessible by computers and the information is displayed on the computer display monitor. Information provided by these services include the program schedules for the major terrestrial stations as well as cable networks.
The data presented by the Internet services are described in graphical form, such as HTML. The PC simply displays the EPG in the way it was sent from the Web Site. This system has a drawback in that the graphical format adds excessive overhead and the attendant throughput problems associated with such large blocks of data. The intelligence for responding to subscriber requests for day/date specific TV schedules, the graphical form in which it is displayed, the sorting abilities, etc. are under the control of the Web Server.
Another conventional system, as disclosed in U.S. Pat. No. 5,121,476 to Yee, provides information to a viewer via a television receiver display. In this conventional method the digital data is superimposed on the analog video signal at the video signal source. When the video signal is received by the television receiver, the digital data, which appears as low-level noise in the received image, is extracted and stored in a memory for selective access and display of the data. In this conventional method, the decoder may be internal or external to the television receiver.
In another conventional system, information is provided to the viewer by obtaining data via a link. Such a system is described in U.S. Pat. No. 4,751,578 to Reiter et al. In this system the video signal from the antenna or cable TV source is received and demodulated. The data is then converted into video data and mixed with the demodulated video signal received from the antenna or cable TV input. Finally, the combination of video data and demodulated video signal is re-modulated and sent to the input of the television receiver for further processing and display to the viewer.